1. Field of the Invention
This invention relates generally to apparatus and methods for performing surgical functions percutaneously on body conduits.
2. Discussion of the Prior Art
As the age of a human body increases, the capacity of its vascular system to carry blood away from and back to the heart tends to degrade. This is caused in part by a hardening of the arteries or by deposits within the arteries which tend to gradually restrict arterial blood flow. When sufficient blood cannot reach an area of the body, the tissue in that area is not supplied with the nutrients and oxygen to sustain and regenerate itself.
Particularly in the aging population, this problem with circulation is particularly noticeable at the extremities, such as the lower leg and foot which are distantly removed from the heart. To supply these extremities with oxygen and nutrients, the blood travels from the heart through an arterial system to the distant location. The venous system gathers the blood at the extremity and returns it through veins back to the heart.
While gravity assists the function of the arteries, it inhibits the function of the veins which must return the blood upwardly through the leg and back to the heart. Assisting each vein in overcoming the gravitational force is a series of vein valves which permit the flow of blood upwardly in the vein, but inhibit the flow of blood downwardly through the vein.
In the past, degradation of the arterial system has been addressed by reconnecting the large saphenous vein in the leg so that it can function as an artery. This provides an additional conduit for transporting blood to the extremities. Although this procedure reduces the capacity of the venous system, it has been found that the remaining veins have been able to accommodate the increased blood flow.
Early procedures required that the saphenous vein be harvested or removed from the leg, turned end-for-end, and reconnected to the arterial system. This turning of vein was required in order to reorient the valves of the vein in a downward direction to facilitate arterial blood flow toward the extremity.
More recently, an insitu procedure has left the saphenous vein in place and the individual valves within the vein have been disrupted. When a valve is disrupted, it no longer functions to inhibit downward flow so that the vein can function as an artery.
As part of this insitu procedure, it is important to occlude the secondary veins which are attached to the saphenous vein. Failure to provide for this occlusion would drive the arterial blood backwardly into the venous system. It is the occlusion of these secondary vessels which is of particular interest to the present invention.
In the past, dye has been injected into the saphenous vein and, using fluoroscopy, the secondary vessels have been identified. In order to occlude these secondary vessels, various mechanisms have been proposed for insertion into the secondary vessel to clog the vessel and stop blood flow. This procedure has not been widely accepted. For one reason, the placement of objects within the vascular system is to be avoided whenever possible. Should the object become dislodged, it could easily migrate to inhibit blood flow in more important regions of the body.
Alternatively, a large incision has been made in the leg in order to gain direct access to the secondary vessel. With this direct access, a suture or clamp has been applied for occlusion. Of course, a large incision is always to be avoided if a less invasive technique can accomplish the same objective.
In either case, the targeting of a secondary vessel has been difficult. As noted, fluoroscopy has been used. However, this passive technique for targeting a secondary vessel is cumbersome, expensive and not particularly accurate.